1. Field of the Invention
This invention relates to umbrellas, and more particularly, to a collapsible frame structure for umbrella with a self-opening mechanism that allows the umbrella, after being collapsed, to be opened automatically without manual effort from the user. Furthermore, each of the second pivotal-coupling device is integrally formed with the inner linking member of the support rib. Therefore, according to the present invention, it is easy and fast in assembly process without having to set a correct position of the second pivotal-coupling device at the supporting rib.
2. Description of Related Art
A collapsible umbrella (also called a foldable umbrella) allows the user to collapse the umbrella when the umbrella is not in use for easy storage or carriage. Collapsible umbrellas are typically provided with a self-opening mechanism that allows the umbrella, after being collapsed, to be opened automatically without manual effort from the user. Conventional collapsible umbrellas, as shown in FIG. 4 is U.S. Pat. No. 6,076,540 which is assigned to the same applicant of the present invention, however, it can not be easily assembled during manufacturing due to setting position of coupling structure of supporting rib in the collapsible frame structure encountering difficulties, which will be illustratively described in the followings.
In assembly, the inner end of the main rib 15 is coupled to the upper running hub 14; the inner end of the supporting rib 17 is coupled to the intermediate running hub 13 and the outer end of the same is coupled to the middle of the main rib 15 by means of the first pivotal-coupling device 16; and the linkage beam 19 is connected to the second pivotal-coupling device 18 by hooking its upper hook and to the bottom running hub 11 by hooking its bottom hook.
The correct coupling position of the second pivotal-coupling device 18 is at the hooking position of the upper hook of the linkage beam 19. It means that the second pivotal-coupling device 18 should be installed at a correct position of the supporting rib 17 with respect to the inner linking member 173. This is because that the elasticity of the spiral spring 12 is related to the force and the speeds of opening and folding an umbrella. The faster the speed, the larger the force required to operate the umbrella. Furthermore, the force and the speeds of opening and folding an umbrella also relate to the correct position of the second pivotal-coupling device 18. Therefore, in mass production, how to fix the second pivotal-coupling device 18 to a correct position at the supporting rib 17 has become an important problem to be resolved.
In general, for increasing the yield, it is often the quality is deteriorated. Furthermore, if the assembly work is performed in night, the quality will further deteriorate.
It is therefore an objective of the present invention to provide a collapsible frame structure for self-opening umbrella, wherein the quality is improved by deleting the carelessness of the operator in assembly process.
Another object of the present invention is to provide a collapsible frame structure for self-opening umbrella, wherein the second pivotal-coupling device of the supporting rib is integrally formed with the inner linking member of the support ribs so as to form a compound pivotal-coupling device. Therefore, the invention is easy and fast in assembly process without having to set the correct position of the second pivotal-coupling device at the supporting rib. Furthermore, the yield ratio will be increased.
A further object of the present invention is to provide a collapsible frame structure for the self-opening umbrella, wherein in storing the umbrella, the linkage beam can be stored in the trench. Therefore, the volume of the frame between the intermediate running hub and the bottom running hub can be reduced. Therefore, an umbrella with two ribs can be stored in compact volume.
In accordance with the foregoing and other objectives of the present invention, an improved collapsible frame structure is provided for self-opening umbrella. The collapsible frame structure of the invention includes:
a main shaft; a bottom running hub slidably mounted on the main shaft; an intermediate running hub slidably mounted on the main shaft; an elastic member mounted on the main shaft between the bottom running hub and the intermediate running hub; an upper running hub fixedly mounted on a top of the main shaft; a plurality of main ribs, each being made from enforced FRP and having one end pivotally linked to the upper running hub; a plurality of supporting ribs having a double-bar beam portion, each being made from enforced FRP and having an outer linking member formed at one end thereof pivotally connected to the main rib, an inner linking member formed at the other end thereof pivotally linked to the intermediate running hub; a plurality of linkage beams, each being made from a steel bar formed with a bottom hook connected to the bottom running hub and an upper hook pivotally coupled to each of the supporting rib; a plurality of first pivotal-coupling devices, each coupling an outer end of each of the supporting rib to each of the main rib, each of the first pivotal-coupling devices including a tubular member to have each of the main rib to pass therethrough and at least one ear formed thereunder with a hole pivotally connected to each of the outer linking member of the supporting rib; a plurality of second pivotal-coupling devices each being made through injection molding with nylon plastics, each coupling the upper hook of each of the linkage beam to each of the supporting rib and each of the second pivotal-coupling devices including a linking member having two parallel through holes formed therein to allow the double-bar beam portion of each of the supporting rib to pass through, said linking member being formed with a plurality of pivotal shafts therebetween so as to be hooked with the upper hook of each of the linkage beams, allowing each of the linkage beam to be pivotally coupled to each of the supporting ribs; and each of the second pivotal-coupling device of the supporting rib being integral formed with each of the inner linking member of the supporting rib so as to form a compound pivotal-coupling device.